The Influence of Surface Building's Relative Position on the Seismic Response of Subway Structures

By using the finite element method and viscoelastic artificial boundary,a soil-structure interaction system is established to simulate the influence of surface buildings on the seismic response of subway structures.The conditions of different relative positions between ground building and subway structure are analyzed.The results indicate that when considering the existence of surface buildings,the relative story displacements and internal forces of subway structures are changed greatly.Further the influence of surface buildings on subway structure changes as the distance increases.     

Geological Structure and Quaternary Activity of the Zhangjiakou Fault, Northern China

Based on detailed field investigations,this paper describes the geometrical characteristics and tectonic activities of the Zhangjiakou fault at the northwest of Beijing. This fault strikes mainly northwest to west,short parts of which strike near east to west,dipping north,and extends over a length of 70km. It is a major geological and geomorphological margin,controlling the neotectonic movement in this region. On the south side of the Zhangjiakou fault are the Late Quaternary unconsolidated deposits,forming basins; while on the other side are Mesozoic volcano debris and Pre-Mesozoic metamorphic rocks, forming lower mountains and hills. The Zhangjiakou fault consists mainly of high-angle inverse strike-slip fault and partially of normal strike-slip fault. Among these,the north-dipping NW-NWW-trending secondary faults,constituting the main fracture of the fault,have inverse characteristics; those near the EW-trending secondary faults are links of the former faults,with a smaller length and normal faulting characteristics. Thus,the Zhangjiakou fault is a north-dipping inverse and partially south-dipping normal strike-slip fault. The Zhangjiakou fault has been continuously active since the Quaternary. With the exception of the western end extension,which has been active since the late Pleistocene, the main part of the fault has been active since the Holocene. The central main segment of the Zhangjiakou fault is more active. Since the mid-late period of the late Pleistocene,the average vertical slip rate of a single fault has been over 0. 07mm /a ～ 0. 30mm /a. The Zhangjiakou fault has multi-slip surfaces,and the total vertical slip rate reaches 1. 33mm /a,estimated from the Qingshuihe river terraces and the relevant drilling data.     

Deposition Process of Dust Microparticles from Aerosol to Snow-Firn Pack on Glacier No. 1 in Eastern Tianshan Mountains, China

Samples were continuously collected from aerosol, fresh snow, and snow pits on Glacier No. 1 at Urumqi River source in eastern Tianshan (天山) Mountains. The deposition processes and the characteristics of mineral dust microparticles from aerosol to fresh snow, and then evolution to the snow pit were determined. Total dust microparticle concentration in the surface snow and aerosol showed a similar temporal variation trend, which was strongly associated with regional and local at-mospheric circulation in the ...     

六盘水市地质灾害现状调查及防治

六盘水市为地质灾害多、高发区,近年罕见的灾害性天气诱发隐患点大增,全市防治工作面临新的挑战.在对2010年地质灾害现状调查的基础上,分析和总结地质灾害特点及防治工作现状,并有针对性地提出了防治建议.     

潜孔锤微型桩技术在广元市凤凰山公园滑坡应急治理中的应用

微型桩技术广泛应用于地质灾害应急抢险治理工程中.凤凰山公园滑坡应急治理工程中,在调查滑坡地理条件、地质条件和基本特征的基础上,采用潜孔锤微型钻孔灌注桩技术,辅以挡土板和格构砼的综合治理方案.结果表明工程安全、快速、高效、造价低、质量高,治理效果明显.     

Upper mantle P-wave tomography across the Longmenshan fault belt from passive-source seismic observations along Aba-Longquanshan profile

A passive seismic experiment across the Longmenshan (LMS) fault belt had been conducted between August 2006 and July 2007 for the understanding of geodynamic process between the Eastern Tibet and Sichuan basin. We herein collected 3677 first P arrival times with high precision from seismograms of 288 teleseismic events so as to reconstruct the upper mantle velocity structure. Our results show that the depth of the Lithosphere–asthenosphere boundary (LAB) changes from 70 km beneath Eastern Tibet to about 110 km beneath Longquanshan, Sichuan Basin, which is consistent with the receiver function imaging results. The very thin mantle part of the lithosphere beneath Eastern Tibet may suggest the lithosphere delamination due to strong interaction between the Tibetan eastward escaping flow and the rigid resisting Sichuan basin, which can be further supported by the existences of two high-velocity anomalies beneath LAB in our imaging result. We also find there are two related low-velocity anomalies beneath the LMS fault belt, which may indicate magmatic upwelling from lithosphere delamination and account for the origin of tremendous energy needed by the devastating Wenchuan earthquake.     

六盘水市煤炭资源开发利用结构调整与优化的探讨

六盘水市矿产资源丰富,尤以煤炭为主,但从目前煤炭资源开发利用现状来看,其结构布局尚欠合理,开发利用方式比较粗放,存在＂采富弃贫、大矿小开、一矿多开、技术落后、安全条件差、资源回收率低＂等现象,环境保护与恢复治理的难度也越来越大。为了提高煤炭资源开采利用效率,从规模结构、技术结构、产品结构三个方面提出了六盘水市煤炭资源开发利用结构调整与优化方法：要求新建矿山在30万t/a以上,最低服务年限不低于25年,将目前的小型煤矿山减少到125个;采用高新技术和先进技术,促进矿企产业升级;进行产品结构调整,改变采矿、选矿、冶炼方式,实现集约型经营。     

“中国天然氧吧”品牌效益评估指标体系构建与应用——以江西省乐安县为例

开展“中国天然氧吧”品牌效益评估,对推动生态产品价值转换具有重要意义。运用层次分析法从生态效益、经济效益、社会效益三个方面构建了“中国天然氧吧”品牌效益评估指标体系,并细化为23个具体指标。结合模糊综合评价法,以江西省乐安县为例进行实际应用检验。结果表明：1）此效益评估体系和评估方法具有科学性和合理性,评价结果可以为政府部门合理开发旅游气候资源、推动“中国天然氧吧”品牌可持续发展提供借鉴。2）乐安县“中国天然氧吧”品牌综合效益属“良好”等级。3）针对低评分指标,提出当地政府需要加强生态环境保护规划、生态旅游开发力度和品牌宣传推广等建议。     

桂林岩溶区民宅基地地质灾害分析及防治措施

胆陂村安置点位于桂林侵蚀溶蚀弧峰平原亚区,岩溶强烈发育,工程建设前及建设中均会遇到或发生一系列地质灾害.详细预测评估、针对性提出防治措施,可以确保住宅建设安全,可供同类地区建设借鉴.     

四川盆地西北缘早-中三叠世界线附近沉积岩地球化学特征及古环境意义

通过分析四川盆地峨眉山地区嘉陵江组-雷口坡组沉积岩元素地球化学及碳、氧同位素特征,探讨了其古环境意义,为四川盆地西北缘早-中三叠世古环境研究提供基础信息。结果表明：样品∑(CaO+MgO+LOI)为13.98%～93.31%,反映了相对动荡的沉积环境。δ¹³C值的变化范围是-6.95‰～0.36‰,δ¹⁸O值变化范围为-9.06‰～-0.99‰,δ¹³C值总体表现趋势为降低-升高-降低-升高。海水盐度呈现先升高、后降低、复又升高的多段式变化;海水温度7.11～34.94℃,平均温度21.99℃,古海水温度经历了降低-升高-降低的变化趋势,在早-中三叠世界线附近温度急剧升高。研究区整体处于氧化的沉积环境,间有贫氧的沉积环境出现。以上各个地球化学指标间耦合关系较好,一致反映了研究区早-中三叠世为相对潮湿-相对干热-相对潮湿气候下的海相沉积环境。